An OLED (organic light-emitting diode) device can emit light by itself through an organic layer, because the OLED device does not need a back light, the OLED device has a faster response time and a greater viewing angle. Besides, the OLED device also has the advantages of higher contrast, lighter weight, low power consumption, and capable of being prepared by a flexible substrate, and the OLED device is considered as the panel display device with the greatest development potential.
However, the life issue of the OLED device restricts the pace of its industrialization. Each component of the OLED device is easy to be eroded by water and oxygen, which leads to the damage of pixels, thus shorten the life of the device, therefore, the OLED device needs an effective packaging process to prevent the invasion of the water vapor and oxygen and prevent the aging of the organic material, so as to extend the life span of the OLED device.
The OLED device prepared on the flexible substrate also needs to be packaged. The methods for packaging the flexible OLED device mainly comprise two kinds: covering plate packaging and film packaging. Because the film packaging is easy to be implemented in the flexible packaging of the OLED device, therefore the film packaging has been widely used. The film packaging method usually uses a mask plate to form the film in vacuum, that is, the area that does not need to be packaged, the area for the leading wires in the following up process and the circuit leading wires is exposed on the surface, to facilitate the operation of the following up process. But when forming the film in vacuum, the masking shadow phenomenon as shown in FIG. 1 often occurs, that is when forming the film, the film of the package layer 2 will grow to the area under and covered by the mask plate 1, this is likely to cover the circuit leading wire portion, which will seriously affect the following up process and accordingly the quality of the product. Besides, the mask shadow can cause the increase of the size of the film 2, thus affect the precision of the alignment, causing an incomplete packaging of the effectively light-emitting area of the OLED device or packaging in an excessive width region, so as to affect the circuit wiring part and cannot achieve a design of a narrow margin.